Robert james thompson



(No Model.

B. J. THOMPSON. JACK.

No. 511,867. Patented Jan. 2, 1894.

WITNESSES" INVENTOH Kb" imsERr J! IWOMPJ'OM UNJITED grates PATENT @rrrce.

ROBERT JAMES THOMPSON, OF GRANDIN, MISSOURI.

SPECIFICATION forming part of Letters Patent No. 511,867, dated January 2, 1894.

Application filed March 11 1893. Sen'al No. 465,649. (No model.)

To aZZ whom it may concern.-

Be it known that 1, ROBERT JAMES THOMP- SON, a citizen of the United States, residing at Grandin, in the county of Carter and -tate of Missouri, have invented certain new and useful Improvements in Jacks; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to new and useful improvement in lifting jacks.

The object of this invention is to simplify the construction of devices of this character, and make them safe and more convenient in use by means of the operating lever, which automatically locks the jack when said lever is parallel with the post of the jack, and also to arrange the parts of the jack in such manner thatit canbe readily and easily handled and operated, and which are strong and durable, efiective in the desired result, and comparatively inexpensive in manufacture.

In the accompanying drawings, Figure 1 is a side view of the improved jack, in which the dotted lines show the operating lever in position, and ready to raise the load, and the solid lines show the position of the lever after the load has been raised. Fig. 2 is an end View. Fig. 3 is a sectional view of the jack on line 00 00.

Like letters of reference indicate corresponding parts of the several views.

Referring to the drawings, the letter A designates the T-shaped supporting post of the jack, and is supported and fastened to the base B, which is bolted to the bed plate 0, and has the truss rod D to support the frame under heavy loads.

E is a pulley bracket and is fastened to the T-shaped post at e, and has the pulley f.

G is the lifting arm and is provided with the anti-friction steel roller 9, and grooves h to guide the lifting arm.

J is the operating lever and is provided with the L-shaped catch K, which is pivoted to the lever at. 70, and has the slot 10 to receive the chain. The catch K can be inverted to receive the chain. The operating lever is mounted on the bracket N, which is secured to the supporting post. i

M is a chain and is fastened to the lifting arm at m, and passes upward and over the pulleyf, and one of the links is then admitted into the slot in the catch K.

I do not confine myself to the use of a chain, but a rope or wire cable may be used as well with a slight modification of the catch.

It is obvious that many minor changes might be made in the several parts and substituted for those shown and described without in the least departing from the nature or spirit of the invention.

Having thus described the invention, what is claimed as new is- 1. A lifting jackcomprising the T-shaped supporting post A, the pulleyf, and bracket E, a lifting arm Gslidable on the supporting post andprovided withthe anti-friction steel roller g, an operating lever J provided with the catch K and mounted on the lever bracket N, a chain passing over the pulleyf, and connected to the lifting arm G and to lever J, a base B, and bed plate 0, with the truss rod D, substantially as described.

2. A lifting jack comprising the T-shaped vertical post a piilley and bracket, the bracket attached to the top of the post, a chain over said pulley, a lever bracket attached to the post, an operating lever pivoted in said bracket and provided with a catch to receive the chain, a lifting arm siidable on the T- shaped post, with an anti-friction steel roller on said arm, a base and bed plate, a truss rod from bed plate to post, substantially as described.

3. In a lifting jack the combination of a base and bed plate, a T-shaped vertical post, a lifting arm slidable thereon and provided with the anti-friction steel roller, a chain attached to said lifting arm, a pulley bracket 5 fastened to the T-shaped post, a pulley pivmeans for holding the chain securely in posird tion, substantially as described. ,7

In testimony whereof I affix my signature in presence of two witnesses.

otally mon nted in said bracket, alever bracket ROBERT JAMES THOMPSON Witnesses:

J. B. CAMPBELL, RICHARD L. MOBREY.

attached to the vertical T post, a lever pivoted to said bracket, and provided with an L-shaped catch pivoted to the lever with 

